[201/lab sheet] Make ssh authorised key bit more clear

201/Lab-Sheet.md

@@ -185,8 +185,8 @@ _If your **local machine** is a Linux computer, then this is the section for you
 
 If you are using Linux on your _local machine_ generate your own public-private keypair like so:
 
-
 ```bash
+mkdir $HOME/.ssh
 ssh-keygen -t ed25519
 ```
 
@@ -242,13 +242,14 @@ When you’re done, click the "save private key" button and select a secure loca
 
 If you have not entered a passphrase, you will be asked to confirm that you want to save the key without one. We strongly recommend using a passphrase, but you can press enter to bypass this prompt.
 
-Next, you need to tell your server about your new SSH key. This is done by editing the `~/.ssh/authorized_keys` file. Do that like this:
+Next, you need to tell your server about your new SSH key. This is done by editing the `~/.ssh/authorized_keys` file. The `~/.ssh/` directory might not exist, so we may need to create that too. Do that like this:
 
 ```bash
+mkdir ~/.ssh/;
 nano ~/.ssh/authorized_keys
 ```
 
-Paste in your public key that saved earlier. Save it and exit, and then ensure it has the correct permissions like so:
+Of course, don't worry about any errors telling you that `~/.ssh/` already exists. Next, paste in your public key that saved earlier into the `nano` text editor. Save it and exit (Ctrl + X, then Y, then Enter), and then ensure it has the correct permissions like so:
 
 ```bash
 chown -R username:username ~/.ssh